The goal of the project is to evaluate the potential of human monocyte/neutrophil elastase inhibitor (HEI) as a pharmaceutical agent for inflammatory diseases of the lung. HEI, a single chain serpin protein, is found at high levels in cells at inflammatory sites. HEI reacts rapidly and irreversibly to inhibit human neutrophil elastase (HNE), the potent protease responsible for degradation of elastin, other matrix proteins and protective regulatory proteins at inflammatory sites. In Phase I, we generated recombinant HEI (rHEI) and in Phase II, we propose to scale-up the insect cell production system and adapt purification protocols for large batches of rHEI. We will produce 1.6 grams of pure rHEI (16 batches of 0.1 gram). In a most important specific aim, we will evaluate the efficacy of pure rHEI by examining its capacity to function in a simulated human inflammatory environment, sputum of cystic fibrosis patients. Efficacy will also be examined in vivo by a multi-parameter rat model in which lung damage is induced by instilled HNE or cystic fibrosis sputum. We will examine pulmonary distribution and clearance or rHEI in the rat using confocal microscopic approaches. Preliminary toxicity evaluation will be done in mice. Stability of pure rHEI will be examined on storage and on aerosol treatment and exposure to oxidants; interactions of pure rHEI with systems of the blood will be examined. Collectively, these integrated preclinical examinations will establish the potential of rHEI as a pharmacological agent for treatment of inflammatory lung diseases. PROPOSED COMMERCIAL APPLICATION: Inflammatory lung diseases account for a large amount of pain and suffering and lost accomplishments worldwide. There is a great need for an agent that will effectively inhibit, without side effects, the degradative action of neutrophil elastase responsible for injury to inflamed lungs. The market for anti-inflammatory agent for lung diseases is in excess of 50 million dollars in the U.S.